using MembranePoreTester.Models;
using System.Collections.Generic;
using System.Linq;

namespace MembranePoreTester.Helpers
{
    public static class PoreDistributionAnalysis
    {
        public static double CalculateAveragePore(
            IEnumerable<DataPoint> points,
            string unit,
            TestLiquid liquid)
        {
            var sorted = points.OrderBy(p => p.Pressure).ToList();
            if (sorted.Count < 2) return 0;

            double[] pressures = sorted.Select(p => p.Pressure).ToArray();
            double[] dryFlows = sorted.Select(p => p.DryFlow).ToArray();
            double[] wetFlows = sorted.Select(p => p.WetFlow).ToArray();

            double halfDryFlow = dryFlows.Max() / 2.0;

            // 找到湿膜流量等于 halfDryFlow 的压力（交点）
            for (int i = 0; i < wetFlows.Length - 1; i++)
            {
                if ((wetFlows[i] <= halfDryFlow && wetFlows[i + 1] >= halfDryFlow) ||
                    (wetFlows[i] >= halfDryFlow && wetFlows[i + 1] <= halfDryFlow))
                {
                    double p = Interpolation.Linear(
                        new[] { wetFlows[i], wetFlows[i + 1] },
                        new[] { pressures[i], pressures[i + 1] },
                        halfDryFlow);
                    return PoreCalculator.PressureToPore(p, unit, liquid);
                }
            }
            return 0;
        }




        public static double CalculatePoreRangePercentage(
    IEnumerable<DataPoint> points,
    string unit,
    TestLiquid liquid,
    double lowerPore,
    double upperPore)
        {
            var sorted = points.OrderBy(p => p.Pressure).ToList();
            if (sorted.Count < 2) return 0;

            // 提取有效点（流量 > 0）
            var wetValid = sorted.Where(p => p.WetFlow > 0).Select(p => (Pressure: p.Pressure, Flow: p.WetFlow)).ToList();
            var dryValid = sorted.Where(p => p.DryFlow > 0).Select(p => (Pressure: p.Pressure, Flow: p.DryFlow)).ToList();

            if (wetValid.Count < 2 || dryValid.Count < 2) return 0;

            // 有效压力重叠区间
            double minPressure = Math.Max(wetValid.First().Pressure, dryValid.First().Pressure);
            double maxPressure = Math.Min(wetValid.Last().Pressure, dryValid.Last().Pressure);
            if (minPressure >= maxPressure) return 0;

            // 孔径转压力
            double pLower = PoreCalculator.PoreToPressure(upperPore, unit, liquid);
            double pUpper = PoreCalculator.PoreToPressure(lowerPore, unit, liquid);

            pLower = Math.Max(pLower, minPressure);
            pUpper = Math.Min(pUpper, maxPressure);
            if (pUpper <= pLower) return 0;

            // 在有效点集上插值
            double qWetLower = InterpolateOnValid(wetValid, pLower);
            double qDryLower = InterpolateOnValid(dryValid, pLower);
            double qWetUpper = InterpolateOnValid(wetValid, pUpper);
            double qDryUpper = InterpolateOnValid(dryValid, pUpper);

            if (qDryLower <= 0 || qDryUpper <= 0) return 0;

            double ratioLow = qWetLower / qDryLower;
            double ratioHigh = qWetUpper / qDryUpper;
            double result = (ratioHigh - ratioLow) * 100;
            return result < 0 ? 0 : result;
        }

        // 辅助插值函数：基于有效点列表（已按压力升序）
        private static double InterpolateOnValid(List<(double Pressure, double Flow)> validPoints, double pressure)
        {
            if (validPoints.Count == 0) return 0;
            if (pressure <= validPoints[0].Pressure) return validPoints[0].Flow;
            if (pressure >= validPoints[^1].Pressure) return validPoints[^1].Flow;

            for (int i = 0; i < validPoints.Count - 1; i++)
            {
                if (pressure >= validPoints[i].Pressure && pressure <= validPoints[i + 1].Pressure)
                {
                    double p1 = validPoints[i].Pressure;
                    double f1 = validPoints[i].Flow;
                    double p2 = validPoints[i + 1].Pressure;
                    double f2 = validPoints[i + 1].Flow;
                    return f1 + (f2 - f1) * (pressure - p1) / (p2 - p1);
                }
            }
            return 0;
        }
    }
}